A Deuterium Glow Discharge with a ZrD2 Cathode on the Wall for Checking the Putative Fusion D + D à 4He + Heat
Kjeld C. Engvild, DTU Environment, DK-4000 Roskilde, Denmark
A fusion reaction of D + D à 4He + heat has been proposed repeatedly in LENR experiments where helium is typically found in high amounts, tritium in low amounts, and only few neutrons; the heat evolution corresponds to the amount of helium, observed in both electrolysis and glow discharge experiments. The D + D à 4He + Q reaction is not recognized in physics, as there is no obvious mechanism for converting MeV energy directly into heat. A deuterium glow discharge “lamp” with a cathode consisting of a deuterated zirconium foil fitted snugly to the tube wall and an anode in the center might be used to investigate putative excess heat by classical water calorimetry. The lamp should be operated at as low pressure and current as feasible, with proper precautions against X- and gamma-rays.
In 2015 Dalkarov et al. published experiments on low energy hydrogen isotope bombardment of titanium and titanium deuteride water cooled targets at 10-50 keV and a few watts. At deuteron bombardment on titanium deuteride at one watt the temperature rose about 80 degrees C; when bombarding titanium with protons, the temperature rose only about 20 degrees. Have Dalkarov et al observed fusion reactions at four times above break-even? They themselves asked the question: do we have a D + D à 4He + Q reaction? Such a reaction is not recognized in physics, as there is no obvious mechanism for converting MeV energy directly into heat. However, there have been numerous results in LENR literature that heat evolution corresponds to 4He production, while the production of tritium is quite low and there are only very few neutrons (review Storms, 2012). This has been observed in many electrolysis experiments, but also in glow discharge experiments (Karabut et al. 1992).
Perhaps the Daskalov experiment could be replicated in a simple manner in a special low pressure glow discharge “lamp” with a large area cathode in close contact with the tube wall.
A tube filled with deuterium, a center tungsten anode, a cathode connected to a foil of zirconium, electrolytically loaded with deuterium to almost ZrD2 is fitted snugly to the wall. The “lamp” should be run at as low pressure and current as feasible to obtain as long free deuteron path as possible. Proper precautions against X- and gamma rays should be taken. Heat evolution is measured by simple water calorimetry in a Dewar.
A claim of D + D à 4He + heat is dismissed by the physics community, as there is no obvious mechanism for converting MeV energy into heat. A possibility might be a three-body reaction (Takahashi et al. 1999, Kasagi et al. 1995, 2002, Engvild 1998) between three deuterons that interact with the metal lattice. An incoming deuteron interacts with two D’s and form an extended Efimov assembly of three D’s (Ferlaino and Grimm 2010, Naidon and Endo 2017). The assembly knocks on the atoms in the lattice, and it is sometimes elevated to the next Efimov state at higher energy, but with a size of only 1/22 of the former state (Ferlaino and Grimm 2010). Three D’s so close together would fuse almost instantaneously, most often:
D + D + D à (DDD) à 4He + D,
but also, rarely à (DDD) à 3He + T.
Neutrons would only be formed in secondary reactions with accelerated tritons and deuterons.
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